Configuring SDM Templates

This chapter describes how to configure the Switch Database Management (SDM) templates on the Catalyst 3750-E or 3560-E switch. Unless otherwise noted, the term switch refers to a Catalyst 3750-E or 3560-E standalone switch and to a Catalyst 3750-E switch stack.

Note For complete syntax and usage information for the commands used in this chapter, see the command reference for this release.

Understanding the SDM Templates

You can use SDM templates to configure system resources in the switch to optimize support for specific features, depending on how the switch is used in the network. You can select a template to provide maximum system usage for some functions; for example, use the default template to balance resources, and use access template to obtain maximum ACL usage.

To allocate hardware resources for different usages, the switch SDM templates prioritize system resources to optimize support for certain features. You can select SDM templates for IP Version 4 (IPv4) to optimize these features:

•Routing—The routing template maximizes system resources for unicast routing, typically required for a router in the center of a network.

•VLANs—The VLAN template disables routing and supports the maximum number of unicast MAC addresses. It would typically be selected for a Layer 2 switch.

•Default—The default template gives balance to all functions.

•Access—The access template maximizes system resources for access control lists (ACLs) to accommodate a large number of ACLs.

The switch supports only the desktop templates.

Table 8-1 lists the approximate numbers of each resource supported in each of the four templates for a desktop switch.

Table 8-1 Approximate Number of Feature Resources Allowed by Each Template

Resource

Access

Default

Routing

VLAN

Unicast MAC addresses

4 K

6 K

3 K

12 K

IGMP groups and multicast routes

1 K

1 K

1 K

1 K

Unicast routes

6 K

8 K

11 K

0

•Directly connected hosts

4 K

6 K

3 K

0

•Indirect routes

2 K

2 K

8 K

0

Policy-based routing ACEs

0.5 K

0

0.5 K

0

QoS classification ACEs

0.5 K

0.5 K

0.5 K

0.5 K

Security ACEs

2 K

1 K

1 K

1 K

VLANs

1 K

1 K

1 K

1 K

The first eight rows in the tables (unicast MAC addresses through security ACEs) represent approximate hardware boundaries set when a template is selected. If a section of a hardware resource is full, all processing overflow is sent to the CPU, seriously impacting switch performance. The last row is a guideline used to calculate hardware resource consumption related to the number of Layer 2 VLANs on the switch.

Dual IPv4 and IPv6 SDM Templates

You can select SDM templates to support IP Version 6 (IPv6). For more information about IPv6 and how to configure IPv6 unicast routing, see "Configuring IPv6 Unicast Routing."

This software release does not support IPv6 multicast routing and QoS.

This software release does not support Policy-Based Routing (PBR) when forwarding IPv6 traffic. The software supports IPv4 PBR only when the dual-ipv4-and-ipv6 routing template is configured.

The dual IPv4 and IPv6 templates allow the switch to be used in dual stack environments (supporting both IPv4 and IPv6). Using the dual stack templates results in less hardware capacity allowed for each resource. Do not use them if you plan to forward only IPv4 traffic. These SDM templates support IPv4 and IPv6 environments:

•Dual IPv4 and IPv6 default template—supports Layer 2, multicast, routing, QoS, and ACLs for IPv4; and Layer 2, routing, and ACLs for IPv6 on the switch.

SDM Templates and Switch Stacks

In a Catalyst 3750-E-only or a mixed hardware switch stack, all stack members must use the same SDM desktop template that is stored on the stack master. When a new switch is added to a stack, the SDM configuration that is stored on the stack master overrides the template configured on an individual switch. For more information about stacking, see Chapter 5, "Managing Switch Stacks."

You can use the show switch privileged EXEC command to see if any stack members are in SDM mismatch mode. This example shows the output from the show switch privileged EXEC command when an SDM mismatch exists:

Switch# show switch

Current

Switch# Role Mac Address Priority State

------------------------------------------------------------

*2 Master 000a.fdfd.0100 5 Ready

4 Member 0003.fd63.9c00 5 SDM Mismatch

This is an example of a syslog message notifying the stack master that a stack member is in SDM mismatch mode:

2d23h:%STACKMGR-6-SWITCH_ADDED_SDM:Switch 2 has been ADDED to the stack (SDM_MISMATCH)

2d23h:%SDM-6-MISMATCH_ADVISE:

2d23h:%SDM-6-MISMATCH_ADVISE:

2d23h:%SDM-6-MISMATCH_ADVISE:System (#2) is incompatible with the SDM

2d23h:%SDM-6-MISMATCH_ADVISE:template currently running on the stack and

2d23h:%SDM-6-MISMATCH_ADVISE:will not function unless the stack is

2d23h:%SDM-6-MISMATCH_ADVISE:downgraded. Issuing the following commands

2d23h:%SDM-6-MISMATCH_ADVISE:will downgrade the stack to use a smaller

When you use the VLAN template, no system resources are reserved for routing entries, and any routing is done through software. This overloads the CPU and severely degrades routing performance.

•Do not use the routing template if you do not have routing enabled on your switch. To prevent other features from using the memory allocated to unicast routing in the routing template, use the sdm prefer routing global configuration command.

•If you try to configure IPv6 without first selecting a dual IPv4 and IPv6 template, a warning message appears.

•Using the dual stack template results in less hardware capacity allowed for each resource, so do not use it if you plan to forward only IPv4 traffic.

Setting the SDM Template

Beginning in privileged EXEC mode, follow these steps to use the SDM template to maximize feature usage:

•vlan—Maximizes VLAN configuration on the switch with no routing supported in hardware.

Use the no sdm prefer command to reset the switch to the default desktop template. The default template balances the use of system resources.

Step 3

end

Return to privileged EXEC mode.

Step 4

reload

Reload the operating system.

After the system reboots, you can use the show sdm prefer privileged EXEC command to verify the new template configuration. If you enter the show sdm prefer command before you enter the reload privileged EXEC command, the show sdm prefer command shows the template currently in use and the template that will become active after a reload.

This is an example of an output display when you have changed the template and have not reloaded the switch:

Switch# show sdm prefer

The current template is "desktop routing" template.

The selected template optimizes the resources in

the switch to support this level of features for

8 routed interfaces and 1024 VLANs.

number of unicast mac addresses: 3K

number of igmp groups + multicast routes: 1K

number of unicast routes: 11K

number of directly connected hosts: 3K

number of indirect routes: 8K

number of qos aces: 0.5K

number of security aces: 1K

On next reload, template will be "desktop vlan" template.

To return to the default template, use the nosdm prefer global configuration command.

This example shows how to configure a switch with the routing template:

Switch(config)# sdm prefer routing

Switch(config)# end

Switch# reload

Proceed with reload? [confirm]

This example shows how to configure the IPv4-and-IPv6 default template on a desktop switch:

Switch(config)# sdmprefer dual-ipv4-and-ipv6 default

Switch(config)# exit

Switch# reload

Proceed with reload? [confirm]

Displaying the SDM Templates

Use the show sdm prefer privileged EXEC command with no parameters to display the active template.